# Read names, chop off numbers
my @names = map /\.(.*)/, <DATA>;

# Pair them up randomly
for (1..@names/2) {
  printf "Group $_: %s and %s are partners\n", splice(@names, rand(@names), 1)
  , splice(@names, rand(@names), 1);
}

##</code><code>##

  printf "Group $_: %s and %s are partners\n", shift(@names), splice(@names, rand(@names), 1);